[clug] Netgear router DNS

[Chris Smart]

On Wed, 26 Dec 2018, at 17:09, Mike Carden via linux wrote:
> Does anyone have experience with Netgear home routers and DNS?
> 

Yes, but only with OpenWRT.

> I have a WNDR3700V4 Netgear router.
> 
> I have a pihole DNS server on my local network. If I edit my laptop’s
> /etc/resolv.conf, I can get it to resolve via pihole.
> 
> What I want to do is get my router to tell DHCP clients to use the pihole
> for DNS.
> 

Normally to advertise different DNS servers to clients you'd use DHCP options, e.g.:

"6,<pi-hole-ip>"

In OpenWRT that's in advanced settings for the network.

It does not look like Netgear supports custom DNS for clients, they only get Netgear's IP:

http://setuprouter.com/router/netgear/wndr3700/dns.htm

> So I set the pihole IP as the ‘Use this DNS’ in the router’s settings, but
> it doesn’t seem to change anything. Before the change, my laptop has the
> router’s Gateway IP as the DNS address in /etc/resolv.conf, and after the
> change and a disconnect/reconnect to the router, it’s still that. But
> clients can’t get DNS.

I think what you're setting there with the "Use this DNS" is the upstream DNS for the router, not what the clients will get.

> 
> I kinda hoped that the router would Do The Right Thing, but it seems not.
> 
> Ideas?
> 

By default the pi hole will be using Netgear's IP. So probably the easiest thing to do is to reconfigure your pi hole to use custom upstream DNS and change the netgear to use pi hole for DNS (as you did already). Then all clients will talk to the router, the router will talk to the pihole and the pihole will talk to wherever directly.

Or you can flash OpenWRT on your router and enjoy the freedoms it provides.

General info on all WNDR models:
https://openwrt.org/toh/netgear/wndr3700

v4 specific, link to binaries:
https://openwrt.org/toh/hwdata/netgear/netgear_wndr3700_v4

-c